A 40-year-old Spanish woman has been arrested for being simultaneously married to three Nigerians who paid her 3,000 euros ($3,952) each to marry them so they would be eligible to be naturalized, police said Friday.

The woman, arrested in Madrid, is accused of a crime against family relations.

The investigation began last month when agents noticed several irregularities in an application for residence made by a person of Nigerian nationality.

Police agents found that the man had married a Spanish woman and afterwards applied for a residence permit with the corresponding marriage certificate.

The agents later discovered that the woman was listed in the marriage registers of other districts of Madrid, having wed two other Nigerians in 2007 and 2008.